DataSet.GetXml not returning null results

Question

I tried the function from this question and I get the following error at the line

row[column] = default(column.DataType);

The error is:

The type or namespace name 'column' could not be found(are you missing a using directive or an assembly reference?)

By the way, I am using VS 2008 and C#. I would appreciate your response in this regard.

Thanks Pankaja